HiPIMS Metal Hardmask Deposition for Low-Stress Wafer Patterning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in semiconductor processing is the difficulty in producing high aspect ratio features with precise critical dimension (CD) resolution, particularly with amorphous carbon hardmasks that have poor etch selectivity and result in intrinsic stresses that cause wafer bowing or warping.
Innovation Solution
A high-power impulse magnetron sputtering (HiPIMS) system is used to deposit metal-containing hardmask layers with controlled stress by varying the energy of the ion beam through cyclic pulses, including primary negative pulses to dislodge target atoms and secondary positive pulses to accelerate them towards the substrate, with differing pulse parameters in alternating cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If amorphous carbon is used as hardmask material, then high aspect ratio features can be formed, but etch selectivity is poor and intrinsic stresses cause wafer bowing or warping
Solution Approach 1:
The patent changes the material parameters by transitioning from amorphous carbon to metal-containing hardmask materials deposited via HiPIMS. This parameter change improves etch selectivity while maintaining high aspect ratio feature formation capability, and allows control of intrinsic stress through pulsed deposition parameters
Solution Approach 2:
The patent employs composite material structure by depositing metal-containing layers with specific compositions (such as tungsten, molybdenum, or their silicides) that combine the high aspect ratio formation capability with improved etch selectivity and controllable stress characteristics
2Quantity of substance
If conventional sputtering is used to deposit metal layers, then deposition is achieved, but intrinsic stress causes wafer bowing or warping
Solution Approach 1:
The patent applies periodic pulsed deposition cycles with alternating polarity pulses (negative and positive) to control the deposition process. This periodic action allows control of ion bombardment energy and deposition rate, thereby managing intrinsic stress accumulation during metal layer formation
Solution Approach 2:
The patent introduces dynamic control of deposition parameters by varying pulse duration, pulse frequency, and pulse amplitude during the deposition process. This dynamic adjustment enables real-time control of stress accumulation, preventing excessive wafer bowing while maintaining deposition efficiency
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for the deposition of metal-containing hardmask layers with reduced intrinsic stress, minimizing wafer bowing and warping, while maintaining high aspect ratio feature formation and precise CD resolution.
Implementation Method 1
applying a primary negative pulse on a target electrode to dislodge target atoms from the target electrode
Implementation Method 2
a secondary positive pulse to accelerate the dislodged target atoms towards the substrate
Implementation Method 3
depositing, in a processing chamber of a high-power impulse magnetron sputtering system, a metal containing layer over a substrate
Data Source
AI summary
An embodiment method includes depositing, in a processing chamber of a high-power impulse magnetron sputtering system, a metal containing layer over a substrate. The depositing includes applying a cyclic plurality of pulses. Each cycle includes applying a primary negative pulse on a target electrode to dislodge target atoms from the target electrode and a secondary positive pulse to accelerate the dislodged target atoms towards the substrate. The secondary positive pulse in one of the cycles is different from the secondary positive pulse in another one of the cycles.